Influence of skin cold sensation threshold in the occurrence of dental sensitivity during dental bleaching: a placebo controlled clinical trial

Abstract Objective This study verified the occurrence of dental sensitivity in patients submitted to a 35% hydrogen peroxide based product (Whiteness HP Maxx 35% - FGM), skin cold sensation threshold (SCST) and its influence on dental sensitivity. Material and Methods Sixty volunteers were divided into 4 groups (n = 15), according to SCST (low: GI and GIII, and high: GII and IV) and bleaching treatment (hydrogen peroxide: GI and GII, and placebo: GIII and GIV). SCST was determined in the inner forearm for 6 different times using a neurosensory analyzer, the TSA II (Medoc Advanced Medical Systems, Ramat Yishai, Northern District, Israel). Dental sensitivity measurements were performed 10 different times using a thermal stimulus and an intraoral device attached to TSA II, positioned in the buccal surface of the upper right central incisor. Spontaneous dental sensitivity was also determined using the Visual Analogue Scale (VAS). Data were submitted to Student's t-test and Pearson's Correlation Test (α=0.05). SCST remained the same during bleaching treatment. Results Distinct responses of dental sensitivity were found in patients with low and high SCST during the first and third bleaching session (p≤0.05). The teeth submitted to the bleaching treatment became more sensitive to cold than those treated with placebo. Moreover, data obtained with TSA and VAS presented moderate correlation. Conclusions Bleaching treatment increased dental sensitivity and skin cold sensation threshold might represent a determining factor in this occurrence, since low and high SCST patients had different responses to the thermal stimulus in the teeth.

Preoperative warming combined with intraoperative skin-surface warming does not avoid hypothermia caused by spinal anesthesia in patients with midazolam premedication

CONTEXT AND OBJECTIVE: Inadvertent perioperative hypothermia is common during spinal anesthesia and after midazolam administration. The aim of this study was to evaluate the effects of intraoperative skin-surface warming with and without 45 minutes of preoperative warming in preventing intraoperative and postoperative hypothermia caused by spinal anesthesia in patients with midazolam premedication. DESIGN AND SETTING: Prospective and randomized study at Hospital das Clínicas, Universidade Estadual Paulista, Botucatu. METHODS: Thirty patients presenting American Society of Anesthesiologists (ASA) physical status I and II who were scheduled for elective lower abdominal surgery were utilized. The patients received midazolam premedication (7.5 mg by intramuscular injection) and standard spinal anesthesia. Ten patients (Gcontrol) received preoperative and intraoperative passive thermal insulation. Ten patients (Gpre+intra) underwent preoperative and intraoperative active warming. Ten patients (Gintra) were only warmed intraoperatively. RESULTS: After 45 min of preoperative warming, the patients in Gpre+intra had significantly higher core temperatures than did the patients in the unwarmed groups (Gcontrol and Gintra) before the anesthesia (p < 0.05) but not at the beginning of surgery (p > 0.05). The patients who were warmed intraoperatively had significantly higher core temperatures than did the patients in Gcontrol at the end of surgery (p < 0.05). All the patients were hypothermic at admission to the recovery room (T CORE < 36° C). CONCLUSIONS: Forty-five minutes of preoperative warming combined with intraoperative skin-surface warming does not avoid but minimizes hypothermia caused by spinal anesthesia in patients with midazolam premedication.

CONTEXTO E OBJETIVO: Hipotermia inadvertida no perioperatório é freqüente durante anestesia subaracnóidea e após a administração de midazolam. O objetivo foi avaliar os efeitos do aquecimento da pele no intra-operatório, associado ou não ao aquecimento da pele durante o período de 45 minutos no pré-operatório, na prevenção de hipotermia intra- e pós-operatória determinada pela anestesia subaracnóidea em pacientes com medicação pré-anestésica com midazolam. TIPO DE ETUDO E LOCAL: Estudo prospectivo e aleatório, realizado no Hospital das Clínicas, Universidade Estadual Paulista (Unesp), Botucatu, SP. MÉTODOS: O estudo foi realizado em 30 pacientes com estado físico ASA (da Sociedade Norte-americana de Anestesiologistas) I e II submetidos à cirurgia eletiva do abdômen. Como medicação pré-anestésica, utilizou-se o midazolam, 7,5 mg via intramuscular (IM) e anestesia subaracnóidea padrão. Em 10 pacientes (Gcontrole) utilizou-se isolamento térmico passivo; 10 pacientes (Gpré+intra) foram submetidos a aquecimento ativo no pré- e intra-operatório; e 10 pacientes (Gintra) foram aquecidos ativamente somente no intra-operatório. RESULTADOS: Após 45 minutos de aquecimento no pré-operatório, os pacientes do Gpré+intra apresentaram temperatura central mais elevada em relação aos dos grupos não aquecidos antes da anestesia (p < 0,05) mas não no início da cirurgia (p > 0,05). Os pacientes que receberam aquecimento no intra-operatório apresentaram temperatura central mais elevada no final da cirurgia em relação aos de Gcontrole (p < 0,05). Todos os pacientes estavam hipotérmicos na admissão da sala de recuperação pós-anestésica (temperatura central < 36° C). CONCLUSÕES: 45 minutos de aquecimento no pré-operatório combinado com aquecimento no intra- operatório não evita, mas minimiza a ocorrência de hipotermia determinada pela anestesia subaracnóidea em pacientes que receberam midazolam como medicação pré-anestésica.

Clear topical ointment decreases transepidermal water loss in jaundiced preterm infants receiving phototherapy.

The evaporation rate (ER) from the skin was measured in 40 jaundiced preterm infants born at less than or equal to 34 weeks of gestation. The baseline measurements were executed in both the right and left side in 3 positions: upper arm, back and lower leg. The patients were randomly recruited to a treatment or a control group. The treatment group received 3.0 ml of clear topical ointment just before phototherapy. Conventional phototherapy was placed above the incubators in both groups. ER and ambient skin temperature were measured at the same point at 30 minutes and 5 hours during phototherapy. In the control group, ER was increased by 8.0 per cent (P value = 0.01) and 14.5 per cent (P value < 0.001) at 30 minutes and 5 hours during phototherapy, respectively. In the treatment group, clear topical ointment decreased ER by 19.2 per cent (P value < 0.001) and 13.2 per cent (P value = 0.003) at 30 minutes and 5 hours during phototherapy, respectively. Ambient skin temperature during phototherapy was increased significantly (P < 0.01) in both groups. Serum microbilirubin difference of pre and post phototherapy at 24 hours of phototherapy between the 2 groups was not significantly different (P = 0.38). The authors concluded that conventional phototherapy, in premature infants nursed in an incubator, increased transepidermal water loss (TEWL) significantly and the application of clear topical ointment on the skin of jaundiced preterm infants receiving conventional phototherapy in incubators reduce TEWL significantly, without effect on serum microbilirubin.

Effect of glucose electrolyte ingestion on physiological changes due to severe heat stress.

Severe heat stress experienced by aircrew during summer months can cause deterioration in performance. Acute heat stress can also lead to dehydration and loss of electrolytes. Previous studies emphasised the need of K+ replacement. This study was carried out to determine the effect of glucose electrolyte ingestion (ELECTRAL) on thermal strain parameters. Ten healthy male subjects in the age group of 19-43 years were exposed to an acute thermal environment of 50 degrees C Tdb with relative humidity of 30% for 40 min. twice each day on two different days with an interval of one hour in between the exposures. At the beginning of rest period electrolyte solution was ingested during electrolyte trials and water under control trials. Physiological parameters of Tsk, T or, HR and electrolyte concentration of Na+ and K+ in sweat did not show any significant difference in both the trials. Sweat loss was significantly higher during electrolyte trials.

Thermal changes produced by norepinephrine application in the preoptic area of monkeys.

The effect of injection of norepinephrine in the anterior regions of hypothalamus on rectal temperature, skin temperature, heart rate and respiratory rate in rhesus monkeys was studied. The injection of 2 micrograms of norepinephrine in the preoptic area produced a fall in body temperature without any accompanying change in skin temperature, heart rate and respiratory rate. The findings suggest that the suppression of heat production may be responsible for the norepinephrine induced hypothermia in monkeys.